Available-for-Sale Debt Investments and Equity Investments - Summary of Available-for-Sale Investments (Details) - USD ($) $ in Millions	Jul. 27, 2019	Jul. 28, 2018
Summary of Available-for-Sale Debt Securities [Abstract]
Amortized Cost	$ 21,590	$ 37,512
Gross Unrealized Gains	111	44
Gross Unrealized Losses	(41)	(547)
Available-for-sale debt investments	21,660	37,009
Net unsettled, available-for-sale investments purchases (sales), net		1,500
U.S. government securities
Summary of Available-for-Sale Debt Securities [Abstract]
Amortized Cost	808	7,318
Gross Unrealized Gains	1	0
Gross Unrealized Losses	(1)	(43)
Available-for-sale debt investments	808	7,275
U.S. government agency securities
Summary of Available-for-Sale Debt Securities [Abstract]
Amortized Cost	169	732
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	(5)
Available-for-sale debt investments	169	727
Non-U.S. government and agency securities
Summary of Available-for-Sale Debt Securities [Abstract]
Amortized Cost		209
Gross Unrealized Gains		0
Gross Unrealized Losses		(1)
Available-for-sale debt investments		208
Corporate debt securities
Summary of Available-for-Sale Debt Securities [Abstract]
Amortized Cost	19,188	27,765
Gross Unrealized Gains	103	44
Gross Unrealized Losses	(29)	(445)
Available-for-sale debt investments	19,262	27,364
U.S. agency mortgage-backed securities
Summary of Available-for-Sale Debt Securities [Abstract]
Amortized Cost	1,425	1,488
Gross Unrealized Gains	7	0
Gross Unrealized Losses	(11)	(53)
Available-for-sale debt investments	$ 1,421	$ 1,435